8 of the craziest proposals for Trump's border wall

This fall, the Trump administration will ask Congress to give the green light on a federal budget that includes funding for a wall along the US-Mexico border.

Not all Republican lawmakers are on board, making it more uncertain that the estimated $21.6 billion wall will become a reality. But the Trump administration is currently reviewing design bids for the project, and says it will reveal the finalists this summer.

Hundreds of construction firms, architects, and artists answered the open call for border wall proposals put out this past spring. Some are more eccentric than others, and many have additional functions beyond securing the border.

The ideas — some of which are in protest of the wall itself — range from parks to hyperloop transit systems. Here are some of the most interesting border wall proposals we've seen.

The pink "Prison-Wall."

Mexican architects from Estudio 3.14, a design firm based in Guadalajara, imagined a hot pink border that stretches 1,954 miles, called the "Prison-Wall."

The renderings are meant to show the impracticality of building the wall, designer Norberto Miranda told Business Insider. He says the border wouldn't foster positive relations with Mexico, and the country's rolling mountain ranges would make construction difficult.

The designers imagined a pink wall, since Trump has said it should be "beautiful." It would include a prison for immigrants, holding up to "11 million people who Trump plans to deport," Miranda said.

A monorail wall with a mall.

A proposal from the National Consulting Service (NCS) calls for a wall with a monorail, which would travel along the 1,900-mile-long border, and a mall.

The National City, California-based firm said the transit system would help revitalize cities on both sides of the border, because the US and Mexico would share profits from transportation fares, according to the LA Times.

"The NCS Team believes the basis of our wall design concept to be a win-win for all; from US National Security, infrastructure, expanded commerce, transport, energy and cost savings efficiencies, and a the US-Mexico build partnership," the proposal's technical summary reads.

A hyperloop wall powered by solar farms.

A group of Mexican and American engineers and urban planners called MADE Collective want to build a $1 trillion hyperloop transportation network as the border wall.

The plan would turn the border into a shared nation, called Otra Nation, with an independent local government and nonvoting representatives in the US and Mexican legislatures, the group told BI.

It would feature several solar farms to power the hyperloop. The designers said an equal number of Americans and Mexicans would build the system.